US2605093A - Detector apparatus for detecting the rate of change of inclination of an object - Google Patents

Description

July 29, 1952 R DORAND DETECTOR APPARATUS FOR DETECTING THE RATE OF CHANGE OF INCLINATION OF AN OBJECT 6 Sheets-Sheet 1 Filed April 15, 1949 July 29, 1952 R, DO'RAND 2,605,093

DETECTOR APPARATUS FOR DETECTING THE RATE OF CHANGE OF INCLINATION OF AN OBJECT Filed April 15, 1949 6 Sheets-Sheet 2 July 29, 1952 R. DORAND DETECTOR APPARATUS FOR DETE CTING 'IIHE RATE OF AN OBJEC OF CHANGE OF INCLINATION 6 Sheets-Sheet 3 Filed April 15, 1949 R. DORAND DETECTOR APPARATUS FOR DETECTIN July 29, 1952 G THE RATE OF CHANGE OF INCLINATION OF AN OBJECT 6 Sheets-Sheet 4 Filed April 15, 1949 July 29, 1952 File d April 15. 1949 R. DORAND 2,605,093 DETECTOR APPARATUS FOR DETECTING THE RATE OF CHANGE OF INCLINATION OF AN OBJECT 6 Sheets-Sheet 5 July'29, 1952 R, DORAND DETECTOR APPARATUS FOR DETECTING THE RATE OF CHANGE OF INCLINATION OF AN OBJECT Filed April 15, 1949 6 Sheets-Sheet 6 Patented July 29, 1952 UN TED, STATE DETECTOR APPARATUS Eon DETECTING THE RATE OF CHANGE INCLINATION v OF AN OBJECT Rene Dorand,-Versail1es, France,assignor A 'mesne assignments, to Etat Francais Application April 15, 1949, Serial No. 87,761

. In France April 23, 1948 .9 Claims. (C1. 264-4)- v 1 v In order to stabilize subject to. unexpected disturbing angular movements, use has already beenmade of arrangements intended for'detecting these disturbances and for acting on control devices for the correction of, these disturbing movements. When use is made, as'detector' of gyratory disturbance, of gyroscopes,' offl pendulous detectors, etc, the latter begin to come into action on the stabilising means for the machine only when the disturbing movementhas reached; already a certain amplitude. The correction ofthe' disturbing effect is thus made with a delay or even at the wrong momentfimore particularly when it is a question oijdisturb'ances of a periodic nature) and the result. obtained is sometimes the reverse of what was sought. for. This is due to the fact that the detectors nientionedabove only record the amplitude of the angular disturbing movement. 1

In order to eliminate this drawback, use has been madealready of detectorsthat are sensitive, not to the amplitude of the disturbing movement of them'achine to be stabilized; but to the speed'of this movement. Inasmuch as the speed factor is in advance of the amplitude factor, these detectors enable the disturbin movement to be corrected efliciently in theory, as soon as it begins to showitself. 1

There are at the present time detectors or indicators of speed of angular deviation known as gyrometers, provided, with a gyroscope with a single degree of play'with flexible return. These instruments exhibit the drawback of having a certain inertia that "is ac'ause of delay in response inherent in the very principle of the gyroscope which entails'a heavy'flywheel. The gyroscope with flexible return has, besides a natural oscillation period, capable of disturbing the action ofthe gyrometer, anoscillation that has to be damped byfa suitable brake. Another drawback of such'gy'rometers lies in the fact that,

if the machines tobe s'tabilized have to be highly accelerated {at the instant of their launching (case of remotely jcontrolled projectiles), the

, mass of the yroscopic flywheel givesrise to abnormal vstrains exerted on the fragile swinging pivots. ,j.

The gyrometers made for effecting the'derivation of the movement in relation to the time, with a view to marking the speed of the disturbin movement, only'beginto give indications capable of being .turnedto account with anappreciable lag over the appearance of the disturbing movement to be corrected; w,

machinessuch as aircraft The angular speed indicators provided with gyroscopes with two degrees of play from which the indications are derived in relation to the time exhibit the drawbacks of gyroscopes, whence the necessity of setting up frictionless relays if it is not desired to putthe gyroscopes out of order and cause precession. effects; a

My invention has for its object to provide-for an angular deviation speed detectoror gyrometer enabling to preventthedrawbacks of .the known apparatus and that maybe employed .to advantage for measuring and recording speeds of angular deviation and the .ang'le'of deviation 'Cfmachines such as aircraft, rockets, ships, etc. and for stabilizing these machines, said gyrometer being characterized by the fact that it comprises a small rotor formed by a hub which is secured on a tiltable shaft driven in rotation around its axis and which carries at least one blade of which at least the free end has a degree of play so that, when the shaft is tilting, saidblade 'end may, during the rotation of the rotor, oscillate or pulsate positively in a meridian plane defined'b'y the axis of rotation of the shaft-and. the longitudinal axis. of the blade, this rotor being combined with stationary recording means for picking-up the pulsation of the blade end-in a stationary reference plane containing the axis of rotation of the rotor and, substantially, thedirection of the angular disturbing movementof the shaft, which occurs-around an axis substantially perpendicular to the axis of rotation of the shaft.

The recording'of the blade end pulsation may be performed by means of electrical contact, capacity variation, self-induction variation etc.

Other particularities and characteristics of the gyrometer make their appearance in the disclosure that'follows and that refers to someexamples of execution of devices given solely as an example and illustrated in quite adiagraminatic way in the accompanying drawings in which:

Figs. 1 to 9 are perspective views of the nine different'forms' of execution or the rotor of the device:

Fig. 10 is a perspective view (cover removed) of an embodiment of .the gyrometerrotor and its bearing system in accordance withthe invention; Fig. 11 is a perspective view partly stripped. of the connection of a dual blade made in one piece,

on the hub ofthe gyrom'eter;

Fig. 12 is a diagrammatic elev'ational view partly in section of the device shown in Fig. 10; Fig.13 is a diagrammatic view of an-embodiment of a complete gyrometer the rotor of which is shown partly and in axial section, the apparatus having condensers for detecting the pulsation of the blade end;

Fig. 14 is a view on a larger scale showing different positions, in the meridian detection plane, of the armatures of elemental condensers of the above embodiment;

Fig. 15 is a view of a modification of the gyrometer furnished with gaseous fluid damping means;

Fig. 16 is a part axial section, on a larger scale, of a modification of execution of the blade in the case of damping by means of gaseous fluid;

Fig. 17 illustrates'a gyrometer, in which the pulsation of the blades of the rotor is recorded by electric contactor means; and

Fig. 18 is a section of a gyrometer with detection and control by means of compressed air.

In Fig. 1, the rotor of the gyrometer comprises three rigid bladesl hinged to the hub 2 by socalled thrust joints 3, each at right angles to the axis 4 of the hub and to the median longitudinal axis of the blade in question, the above mentioned rotor being driven by a motor 5.

In the modification of Fig. 2, the rotor comprises a hub 6 and two diametrically opposite blades 1 of which the hinges 8, contained in the plane of rotation, are not at right angles to the longitudinal axis of the blades.

Fig. 3 illustrates arotor comprising a single 7 In Fig. 5, the rigid blades [6 are connected to the hub H by spring blade connections [8.

In the simpler type of execution as shown in Fig. 6, the blades are flexible thin plates connected 4 directly to the hub 20.

The blademay be connected also, as may be seen in Fig. 7 in which they are denoted by 2|, to the hub 22 by drag joints 23 provided at the ends of a small central rocking lever 24 pivoting at 25 on the hub.

In order to increase the sensitivity of the apparatus, in the case of blades with large supporting surface, an additional degree of play is given to the blades 25 by enabling'them, as may be seen in Fig. 8, to pivot round an axis of change of incidence 2 7 and there are arranged, at the ends of these blades, counter-weights 28 overhanging towards the front part of the blades. In Fig. 9, the blades of the previous examples are replaced by a disc 29- coupled loosely or flexibly round one of its diameters appearing as a spindle 30 carried by the hub I 4. The disc 29 has not necessarily a homogeneous mass distri bution.

In all these forms of execution,the rotor is contained in an enclosure intended for its protection against the wind.

The working principle of the rotor of which some embodiments have been disclosed above is easy to understand. I

When the spindle 40f the rotor (a spindle that is stationary in'relation to the machine to be ward with an angular speed 9 (angle of pitching) the compounding of the speeds (angular speed i) and speed of rotation w of the rotor in relation to the frame of the motor that drives it) gives rise to a compounded centrifugal force of which the maximum, headed upwards, is applied to the blade that crosses the plane comprising the axis of pitching and the axis of rotation of the rotor, the value of this maximum being:

M :21 wSZ wherein I is the moment of inertia of the blade around its pulsation axis.

This alternative force, the frequency of which is equal to the number of revolutions of the rotor,

maintains the pulsation of each blade, this pulsation being damped through the action of the air on the blade; the maximum in amplitude of the pulsation is, in the special case of a pitching slope, in the neighbourhood of the plane of symmetry of the machine to be stabilized and the amplitude of this pulsation is in proportion to the angular deviation speed to be detected.

Thus the angular deviation speeds of the machine on which the rotor referred to above is assembled are materialized by the amplitude of the pulsation of the blades in a meridian plane marking off with the slope plane of the device an angle known as fdephasing that is well defined for a given device, an angle that has only to be taken into consideration in the applications of the device.

As a rule, the device is set up so that the two planes mentioned above are merged, a result that is obtained, for instance, by making use of blades pivoting loosely round a thrust joint meeting the axis of rotation of the rotor and at right angles to this axis and to the longitudinal axis of the blade.

Calculation proves and tests attest that the blades are all the more sensitive in the new detector of angular deviation speed as they are heavier, as their surface is smaller and as the rotary speed of the rotor is less. However, to operate correctly, the surface of the blades must have a certain value, failing this the device would operate as an inclinometer.

The response period of the device is instantaneous in practice, the maximum deviation (pulsation) of a blade being reached when this blade has completed a revolution. If the rotary speed is 20 R. P. S., the response period is therefore less than of a second. V

The friction of the joints of the blades does not give rise to any change, in practice, in the working of the device, on account of the magnitude of the compounded centrifugal forces causing the pulsation. 1

Given that the blades may be light and assembled on sturdy hinges, the inertia effects in the case of machines subjected to high launching accelerations, do not involve any danger of damaging these connections or hinges.

In order to pick-up the deviation of the blade, that is to say the angular deviation speed'and the angle of deviation of the shaft axis, it is suflicient, as shown on Figs. 13 to 18, to provide for a pick-up device for recording the blade pulsation, when said shaft axis executes a tilting motion.

In a practical embodiment of the rotor of the gyrometer and of its bearing device, the apparatus comprises, as shown in Figs; 10 to 12, a frame '50 carrying an electric motor 5 l This frame carries also a cradle 52 in the shape of a crown fascarries a hub 54 on which is connected, round an axis at'right angles to that ofthe'above mentioned spindle; a'double'blade 55.

In the execution of this blade connection as illustrated in Fig. 11, this connection is'formed by two spindleends58 (of which only one is to be seen in the drawing) assembled to slide in the central portion of the double b1adeandof-which the conical ends are engaged in "holes (constituting bearings) of the hub 54. The-engagement of the spindle ends 56in thecorresponding holes of the hub 54 is ensured by a conical pointed screw '5"! engaging with "the rear points of the above mentioned spindlc'ends, and this screw is engaged and clamped in a ta ped plug 53 that is itself screwed in the blade 55, the whole being covered by a hollowed out knob 59 screwed on the plug 58.

In a modification, the above mentioned connection is provided, to advantagefwith ball-bearings.

The circular cradle 52 carries, by means of insulating liners 60, one to four fixed armatures 6| in the shape of a ring-shaped segment.

The angular displacements of the cradle 52 (with the armatures that it carries) in relation to the frame 59 and in two meridian planes at 90 from each other are controlled by means of reducing gear devices, for instance of the screw and nut pattern housed in casings 62 mounted, at 90 from each other, on the frame 59 and actuated, for instance, from devices controlled by the gyrometer.

The cradle is enclosed to advantage in a protecting hooding provided with a bottom 53 and a movable cover '64. In order to avoid in some degree the drawing in rotation of the contained air into the space demarcated by the hooding 535i, the cover 64 is provided to advantage with an inside blading '65 preventing the air to be drawn round with the rotor blades.

In Figs. 13 and 14, the gyrometer comprises a double blade II pivoting round a spindle I52, on the rotor spindle I53 revolving in bearings I54 carried by the stator I55 of the apparatus. The spindle I53 is coupled with a motor 5a.

Each outer blade end shows a periphery in the shape of a spherical segment I56 passing, during the rotation of the rotor, in front of spherical zones I5! of the stator I55. It will be seen at once that whatever may be the amplitude of the blade pulsation, there may not be any unforeseen contact between the rotor and the stator.

Each spherical end I56 carries to advantage, as may be seen more particularly in Fig. 1-4., several condenser elemental armatures I58a, I5Bb, I530, I58d, I58e suitably insulated and connected in parallel to a conductor I59. 4

Each spherical zone I51 carries likewise elemental armatures IBIJa, I601), I600, IIiUd, IBIle, suitably insulated and connected in parallel to a conductor IBI. Each pair of armatures I58a-- IBOa, I58b-I60b, I58c-IBOc, I58d--I60d and I5el60e forms an individual condenser. Fig. 14 shows that, when the blade does not pulsate (zero angular deviation speed) the armatures of the condensers spread over substantially the half of their surface (position Mo), a covering to which substantially corresponds the half-capacity of the condensers. This capacity may vary between a maximum (position Ma) and a minimum (position Mi) in the neighbourhood of zero, according as the blade pulsation is carried out in one direction or the other (in the meridian reference plane going through the spherical zone I5I).

The conductors I59 and IBI are connected to a discriminator '41 of standard pattern which, together with the condensers I58IBI'I, constitutes the recording deviceof thetilting speed and of the tilting angle of the spindle I53.

The discriminator may control the direction of rotation of a reversible motor 48 driving, through a screw-nut system and asuitable rod and lever system, a control member 46 of an aircraft for example. v

In the modification of Figs. Hand '16, the pulsation of the blade or blades is damped through throttling of the air.

In Fig. 15, the blades I51 of the rotor driven by the motor 5b pulsates between two discs I$A I65 integral with the rotor spindle I53. The rotor and its bearin device are connected to a recording system similar to that previously described (Fig.1'3).

In the example of Fig..16, the blade I5I is made up of two blade parts I5Ia and Hill) connected together at their ends by a spherical se ment I56a and the two blade elements mentioned above work together, as in the previous example, with two discs ISL-I 65, so as to throttle the air cushions inclu'dedbetween the bladeand the discs under discussion;

Fig. 17 illustrates an example of complete apparatus having two blades 12 pivoted, at I3, on a hub M which is securedon a shaftf i driven by a motor 5. The recordinggmeans consist of a commutator with two stationary blades 31, '38 and in which the mobilecontact is formed by the blades I 2. This commutator is connected through the conductors 1a, b and through thecommon conductor '0 (in which is mounted a current supply d) to a double-acting relay such as a reversible electric motor '39 driving, by means of a screw system '48 and of a rod system, thecorrector controls d1 of the machine to be stabilized, the blades 31, 38 being carried by the screw 46 carrying out an axial translational movement.

In the example of execution of Fig. 18, the rotor of the 'gyrometer and the ,cradle brought under control "l3 are driven "byfa fluid under pressure (compressed air, "oil'under pressure, etc).

The rotor is started up by means of tangential vjets of fluid under pressure suitably directed (by devices not shown inthe drawing) The blade It is hollow in the same way as the spindle for the rotor and it carrie'sat its enda nozzle I5. The assembly is fed, at I6, with fluid under pressure.

The cradle carries, arranged on the same merid- Ian plane, two openings 11, I8 connected, through pipes 19, 80 to a drivingauxiliary motor 81. According as the cradle is sloped on one side or the other in relationto the blade, the fluid under pressure is sent difierentially .to an auxiliary motor constituted by a cylinder 8| containing a fluid driven piston. The latter may drive directly (or through suitable relays), on the one hand, the controls of a machine to be stabilized (for instance an aircraft) and, on the other hand, through a suitable rack and transmission gear 82, the cradle I3 that it brings into a position so that its plane of symmetry coincides again with the plane of rotation of the blade (pressure of the fluid equal on both sides of the auxiliary motor 8|).

It is clear that the embodiments of the gyrometer as disclosed hereinabove and illustrated in the accompanying drawings have been given only as a non-restrictive guide and that any change in detail may be brought thereto.

What I claim is:

1. Detector apparatus for detecting the rate of change of inclination of an object liable to change its inclination, comprising in combination, a support rotatably mounted on the object for rotation relative thereto about an axis of rotation; drive means operatively connected to said support for rotating the same about said axis of rotation; blade means mounted on said support for rotation therewith, having an inner portion connected to said support and having an outer portion oscillatable in a direction substantially parallel to said axis of rotation, said outer portion of said blade means, when said support is rotated about said axis of rotation, rotating in a normal plane perpendicular to said axis of rotation when the inclination of said object does not change and moving out of said normal plane when the inclination of said object changes; and detector means associated with said blademeans for detecting the amplitude of movement of said outer portion of said blade means out of said normal plane upon change of inclination of said object.

2. Detector apparatus for detecting the rate of change of inclination of an object liable to change its inclination, comprising in combination, a support rotatably mounted on the object for rotation relative thereto about an axis of rotation; drive means operatively connected to said support for rotating the same about said axis of rotation; elongated, rigid blade means mounted on said support for rotation therewith, having an inner end pivotally connected to said support for turning movement about an axis normal to said axis of rotation, and having an outer end oscillatable in a plane defined by said elongated blade means and said axis of rotation, said outer end of said blade means, when said support is rotating about said axis of rotation, rotating in a first plane making a first angle with said axis of rotation when the inclination of said object does not change and moving out of said first plane into a second plane making a second angle with said axis of rotation when the inclination of said object changes; and indicator means mounted on said object and associated with said blade means for indicating the angle between said first and second planes upon inclination of said object.

3. Detector apparatus as defined in claim 1,

and wherein said indicator means comprises at 8 4. Detector apparatus as defined in claim 3 and wherein said moving means is an electric motor.

5. Detector apparatus as defined in claim 4, and wherein said motor is reversible.

6. Detector apparatus as defined in claim 1, and wherein said detector means comprises at least one stationary condenser plate means and at least one movable condenser plate means mounted on said outer portion of said blade means for movement therewith.

7. Detector apparatus as defined in claim 6, and wherein each of said condenser plate means comprises a plurality of arcuate segments formed along circles having their centers located in said axis of rotation.

8. Detector apparatus as defined'in claim 1, and further comprising a fluid damping means mounted on said object and located about said blade means for damping the oscillatory movement of said outer portion thereof.

9. Detector apparatus as defined in claim 1, and wherein said blade means is hollow and said outer portion of said blade means terminates in an open end, and wherein said indicator means comprises a pair of conduits respectively having a pair of open ends respectively located on opposite sides of said normal plane and being adjacent thereto, a cylinder having opposite end portions respectively communicating with said pair of conduits, a piston slidably mounted in said cylinder, and a piston rod connected to said piston for movement therewith; said detector apparatus further comprising a fluid supply means communicating with said hollow blade means for leading a fluid thereto to be ejected from said open outer end of said blade means; and transmission means operatively connected to said piston rod and said pair of open ends of said conduits for moving the latter in a direction parallel to said axis of rotation upon movement of said piston rod, whereby, when said outer portion of said blade meansmoves out of said normal plane, fluid ejected from said outer end of said blade means flows through one of said conduits to move said piston in said cylinder so as to move said conduit ends in said direction parallel to said axis of rotation.

RENE DORAND.

REFERENCES orrnn The following references are of record in the file of this patent:

UNITED STATES PATENTS

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